/**************************************************************************
 * Copyright (C) 2012-2021  Unisound
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 **************************************************************************
 *
 * Description : osal-rbtree.h
 * Author      : yzs.unisound.com
 * Date        : 2021.03.01
 *
 **************************************************************************/
/*
  Red Black Trees
  (C) 1999  Andrea Arcangeli <andrea@suse.de>

  This program is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

  linux/include/linux/rbtree.h

  To use rbtrees you'll have to implement your own insert and search cores.
  This will avoid us to use callbacks and to drop drammatically performances.
  I know it's not the cleaner way,  but in C (not in C++) to get
  performances and genericity...

  Some example of insert and search follows here. The search is a plain
  normal search over an ordered tree. The insert instead must be implemented
  in two steps: First, the code must insert the element in order as a red leaf
  in the tree, and then the support library function rb_insert_color() must
  be called. Such function will do the not trivial work to rebalance the
  rbtree, if necessary.

-----------------------------------------------------------------------
static inline struct page * rb_search_page_cache(struct inode * inode,
                                                 unsigned long offset)
{
        struct rb_node * n = inode->i_rb_page_cache.rb_node;
        struct page * page;

        while (n)
        {
                page = rb_entry(n, struct page, rb_page_cache);

                if (offset < page->offset)
                        n = n->rb_left;
                else if (offset > page->offset)
                        n = n->rb_right;
                else
                        return page;
        }
        return NULL;
}

static inline struct page * __rb_insert_page_cache(struct inode * inode,
                                                   unsigned long offset,
                                                   struct rb_node * node)
{
        struct rb_node ** p = &inode->i_rb_page_cache.rb_node;
        struct rb_node * parent = NULL;
        struct page * page;

        while (*p)
        {
                parent = *p;
                page = rb_entry(parent, struct page, rb_page_cache);

                if (offset < page->offset)
                        p = &(*p)->rb_left;
                else if (offset > page->offset)
                        p = &(*p)->rb_right;
                else
                        return page;
        }

        rb_link_node(node, parent, p);

        return NULL;
}

static inline struct page * rb_insert_page_cache(struct inode * inode,
                                                 unsigned long offset,
                                                 struct rb_node * node)
{
        struct page * ret;
        if ((ret = __rb_insert_page_cache(inode, offset, node)))
                goto out;
        rb_insert_color(node, &inode->i_rb_page_cache);
 out:
        return ret;
}
-----------------------------------------------------------------------
*/

#ifndef _LINUX_RBTREE_H
#define _LINUX_RBTREE_H

#ifdef _WIN32
#else
#define _C99
#endif

#include <stddef.h>

struct rb_node {
  unsigned long rb_parent_color;
#define RB_RED 0
#define RB_BLACK 1
  struct rb_node* rb_right;
  struct rb_node* rb_left;
} /*__attribute__((aligned(sizeof(long))))*/;
/* The alignment might seem pointless, but allegedly CRIS needs it */

struct rb_root {
  struct rb_node* rb_node;
};

#define rb_parent(r) ((struct rb_node*)((r)->rb_parent_color & ~3))
#define rb_color(r) ((r)->rb_parent_color & 1)
#define rb_is_red(r) (!rb_color(r))
#define rb_is_black(r) rb_color(r)
#define rb_set_red(r)           \
  do {                          \
    (r)->rb_parent_color &= ~1; \
  } while (0)
#define rb_set_black(r)        \
  do {                         \
    (r)->rb_parent_color |= 1; \
  } while (0)

static
#ifdef _C99
    inline
#endif
    void
    rb_set_parent(struct rb_node* rb, struct rb_node* p) {
  rb->rb_parent_color = (rb->rb_parent_color & 3) | (unsigned long)p;
}
static
#ifdef _C99
    inline
#endif
    void
    rb_set_color(struct rb_node* rb, int color) {
  rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
}

/**********************************************************/
#ifndef offsetof
#define offsetof(type, member) (size_t) & (((type*)0)->member)
#endif

#ifndef container_of
#define container_of(ptr, type, member)               \
  ({                                                  \
    const typeof(((type*)0)->member)* __mptr = (ptr); \
    (type*)((char*)__mptr - offsetof(type, member));  \
  })
#endif
/**********************************************************/

#define RB_ROOT \
  (struct rb_root) { NULL, }
#ifdef _C99
#define rb_entry(ptr, type, member) container_of(ptr, type, member)
#else
#define rb_entry(ptr, type, member) ((type*)ptr)
#endif

#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
#define RB_EMPTY_NODE(node) (rb_parent(node) == node)
#define RB_CLEAR_NODE(node) (rb_set_parent(node, node))

static
#ifdef _C99
    inline
#endif
    void
    rb_init_node(struct rb_node* rb) {
  rb->rb_parent_color = 0;
  rb->rb_right = NULL;
  rb->rb_left = NULL;
  RB_CLEAR_NODE(rb);
}

extern void rb_insert_color(struct rb_node*, struct rb_root*);
extern void rb_erase(struct rb_node*, struct rb_root*);

typedef void (*rb_augment_f)(struct rb_node* node, void* data);

/* extern void rb_augment_insert(struct rb_node* node, rb_augment_f func,
                              void* data); */
/* extern struct rb_node* rb_augment_erase_begin(struct rb_node* node);
extern void rb_augment_erase_end(struct rb_node* node, rb_augment_f func,
                                 void* data); */

/* Find logical next and previous nodes in a tree */
extern struct rb_node* rb_first(const struct rb_root*);
extern struct rb_node* rb_next(const struct rb_node*);
/* extern struct rb_node* rb_prev(const struct rb_node*);
extern struct rb_node* rb_last(const struct rb_root*); */

/* Fast replacement of a single node without remove/rebalance/add/rebalance */
extern void rb_replace_node(struct rb_node* victim, struct rb_node* new,
                            struct rb_root* root);

static
#ifdef _C99
    inline
#endif
    void
    rb_link_node(struct rb_node* node, struct rb_node* parent,
                 struct rb_node** rb_link) {
  node->rb_parent_color = (unsigned long)parent;
  node->rb_left = node->rb_right = NULL;

  *rb_link = node;
}

#endif /* _LINUX_RBTREE_H */
